In recent years, as magnetic recording media included in magnetic recording and reproducing devices, such as Hard Disk Drives (HDDs), patterned media attract attention (for example, refer to Japanese Patent No. 1888363). Unlike a conventional magnetic recording medium in which crystal grains made of a magnetic material are laid over a disk surface, the patterned medium is a magnetic recording medium processed so that magnetic materials are separated from each other with a non-magnetic material.
As with the conventional medium, the patterned medium includes a data region where data is read and write and a servo region where information for registering a magnetic head is written. However, the magnetic shape in the data region and the shape of the magnetic material in the servo region are different from each other. In general, the shape of each dot made of a magnetic material in the data region is approximately near a cube, whilst the shape of each servo pattern made of a magnetic material in the servo region is a rectangular parallelepiped longer than the shape of the dot.
Meanwhile, when a vertical magnetic recording technique is used as a recording technique for the patterned media, magnetization of the dots and the servo patterns has to be in a direction vertical to a disk surface. However, the shape of the servo patterns is strongly affected by shape magnetic anisotropy compared with crystal magnetic anisotropy, making it difficult to keep magnetization in a vertical direction.
To solve this problem, the servo patterns are required to have a strong coercive force enough so as to eliminate the influence of shape magnetic anisotropy. However, if a strong coercive force is provided also to the dots, it becomes difficult to delete or rewrite data by the magnetic head.
To achieve a patterned medium with contradictory properties, different magnetic materials can be used between the servo patterns and the dots. In this case, however, the manufacturing procedure is complicated, and the cost increases.